Blood pump

Abstract

The present invention relates to an intravascular blood pump 1 for percutaneous insertion into a patient's blood vessel. The blood pump includes a pump casing 2 having a blood inlet 21 and a blood outlet 22, and an impeller 3 rotatably disposed within the pump casing 2 about a rotation axis 10. The impeller 3 has blades 31 sized and shaped to transport blood from the blood inlet 21 to the blood outlet 22. The blood pump 1 includes a drive unit 4 for rotating the impeller 3, the drive unit 4 including a plurality of posts 40 disposed about the rotation axis 10 and a backplate connecting the rear ends of the posts 40, the posts 40 and backplate together forming a magnetic core of the drive unit. A coil winding 47 is disposed around each of the posts 40. The coil windings 82, 83, 86 are controllable to generate a rotating magnetic field, and the impeller 3 includes a magnet structure 32 disposed to interact with the rotating magnetic field to cause rotation of the impeller 3. The magnetic core 400, or a portion thereof, includes a discontinuous soft magnetic material that is discontinuous in electrical conductivity in its cross section, and at least one weld 82, 83, 86 is provided on a surface 811 of the discontinuous soft magnetic material. The weld 82, 83, 86 bridges the at least one discontinuity in electrical conductivity in the discontinuous soft magnetic material. The present invention further relates to a method of fabricating the magnetic core 400, and a method of fabricating the intravascular blood pump 1.

Description

Technical Field

[0001] The present invention relates to a blood pump for assisting blood flow in a patient's blood vessel, in particular, an intravascular blood pump for percutaneous insertion into a patient's blood vessel. The blood pump has an improved drive unit.

Background Art

[0002] Different types of blood pumps are known, such as axial flow blood pumps, centrifugal (i.e., radial) blood pumps, or hybrid blood pumps in which blood flow is caused by both axial and radial forces. An intravascular blood pump is inserted into a patient's blood vessel, such as the aorta, using a catheter. The blood pump typically comprises a pump casing having a blood flow inlet and a blood flow outlet connected by a passage. An impeller or rotor is rotatably supported within the pump casing to create blood flow along the passage from the blood flow inlet to the blood flow outlet, and the impeller is provided with blades for transporting blood.

[0003] The blood pump is typically driven by a drive unit, which can be an electric motor. For example, US Patent Application Publication No. 2011 / 0238172 (A1) discloses an extracorporeal blood pump having an impeller that can be magnetically coupled to an electric motor. The impeller includes a magnet disposed adjacent to a magnet within the electric motor. Due to the attractive force between the magnets within the impeller and within the motor, the rotation of the motor is transmitted to the impeller. To reduce the number of rotating parts, it is also known from US Patent Application Publication No. 2011 / 0238172 (A1) to utilize a rotating magnetic field, and the drive unit has a plurality of fixed posts disposed around a rotation axis, each post holding a wire coil winding and serving as a magnetic core. A control unit sequentially supplies voltage to the coil windings to create a rotating magnetic field. To provide a sufficiently strong magnetic coupling, the magnetic force must be sufficiently high, which can be achieved by supplying a sufficiently high current to the drive unit or by providing large magnets, but this leads to a large overall diameter of the blood pump.

[0004] European Patent No. 3222301 (B1) discloses a blood pump having a magnetic coupling between a drive unit and an impeller, in particular an intravascular blood pump, the blood pump having a compact design, in particular a high ratio of pump capacity to pump size, which results in an outer dimension small enough for the blood pump to be inserted transvascularly, transvenously, transarterially, or transvalvularly, or even smaller for reasons of operation and convenience.

[0005] More specifically, the blood pump in European Patent No. 3222301 (B1) comprises a pump casing having a blood flow inlet and a blood flow outlet, an impeller, and a drive unit for rotating the impeller. By the rotation of the impeller inside the pump casing around the rotation axis, blood can be transported from the blood flow inlet to the blood flow outlet by the blades of the impeller. The drive unit includes a plurality of preferably six pillars and a back plate connecting the rear ends of the pillars and serving as a yoke. The pillars and the back plate constitute the magnetic core of the drive unit. The pillars are circularly arranged around the rotation axis when viewed in a plane perpendicular to the rotation axis, and each of the pillars preferably has a longitudinal axis parallel to the aforementioned rotation axis. Each of the pillars has a coil winding disposed around each of the pillars. The coil windings can be controlled in a coherent manner to generate a rotating magnetic field for driving the impeller. The impeller comprises a magnet structure in the form of magnets arranged so as to interact with the rotating magnetic field and thereby follow its rotation. Summary of the Invention Problems to be Solved by the Invention

[0006] In unpublished European patent application No. 171919400, it has been proposed that discontinuous soft magnetic materials can be used for the magnetic active part of the drive unit, in particular for the posts, in order to keep eddy current losses low. The discontinuous material can be, for example, a laminated material comprising soft magnetic sheets. However, the magnetic active part of the drive unit made of such a material tends to disintegrate and decompose in the layers between the sheets. Another problem arises with respect to the possibility of manufacturing such parts by electrical discharge machining. When an electrical discharge machining contact is made at a specific location on such a workpiece, not all other locations of the material are necessarily in electrical contact with the contacted location. This can complicate the electrical discharge machining.

[0007] The present invention aims to facilitate the manufacture of a drive unit for an intravascular blood pump.

Means for Solving the Problem

[0008] The blood pump of the present invention corresponds to the above-mentioned blood pump as described in European Patent No. 3222301 (B1). Thus, it can be an axial flow blood pump or a mixed flow blood pump that pumps partially axially and partially radially (the diameter of a pure centrifugal blood pump is usually too large for intravascular applications). However, according to one aspect of the present invention, the magnetic core or a part thereof, in particular at least one of the posts, comprises or consists of a discontinuous soft magnetic material that is discontinuous with respect to electrical conductivity in a cross-section transverse to the longitudinal axis of each post. At least one weld is provided on the surface of the discontinuous soft magnetic material, in particular on at least one post. The weld bridges the discontinuity with respect to electrical conductivity within the discontinuous soft magnetic material.

[0009] Each of the columns has a longitudinal axis. Preferably, the longitudinal axis of each column is parallel to the axis of rotation. Each column includes a soft magnetic material that is discontinuous in a cross-section that preferably crosses, and more preferably is perpendicular to, the longitudinal axis of the respective column. In other words, the soft magnetic material of the column is discontinuous in a cross-section that preferably crosses, and more preferably is perpendicular to, the direction of the magnetic flux generated by each coil winding within the column. By dividing or segmenting the soft magnetic material within the cross-section, eddy currents within the column can be reduced or avoided, thereby reducing heat generation and energy consumption. Reducing energy consumption is particularly useful for long-term applications of a blood pump, where it is desirable for the blood pump to be battery-powered to provide mobility to the patient. Also, in long-term applications, the blood pump can operate without purging, which is only possible when heat generation is low.

[0010] As used in this document, "discontinuous" means that the soft magnetic material is separated, segmented, partitioned, or otherwise in a state where, when viewed in any cross-section across the longitudinal axis, it is segmented using an insulating material or other material or a gap to form strictly separated regions of the soft magnetic material, or regions that are segmented but connected at different locations.

[0011] Providing a discontinuous soft magnetic material within a cross-sectional plane transverse to the direction of the magnetic flux reduces eddy currents and, hence, heat generation and energy consumption, as explained above. In order not to significantly weaken the magnetic field compared to a continuous or solid body (i.e., solid) soft magnetic material, the total amount of the soft magnetic material should be maximized while minimizing the continuous regions of the soft magnetic material. This can be achieved, for example, by providing the soft magnetic material in the form of a plurality of sheets of the soft magnetic material, such as electrical steel. In particular, the sheets can form a laminate of sheets. The sheets are preferably electrically insulated from each other, for example, by providing an adhesive, lacquer, baked enamel, or the like between adjacent ones of the sheets. Such a configuration can be referred to as "slotted". Compared to a solid body soft magnetic material, the amount of the soft magnetic material is only slightly reduced, and the amount of the insulating material is kept small, so that the magnetic field generated by the slotted posts is substantially the same as the magnetic field generated by solid posts. In other words, while heat generation and energy consumption can be significantly reduced, the magnetic field loss caused by the insulating material is small.

[0012] The sheets preferably extend substantially parallel to the longitudinal axis of each post. In other words, the sheets may extend substantially parallel to the direction of the magnetic flux, whereby the posts are discontinuous within a cross-sectional plane transverse to or perpendicular to the direction of the magnetic flux. It will be understood that the sheets may extend inclined with respect to the longitudinal axis of each post as long as the soft magnetic material is discontinuous within a cross-sectional plane transverse to the longitudinal axis. The sheets preferably have a thickness in the range of 25 μm to 1 mm, more preferably 50 μm to 450 μm, for example 200 μm.

[0013] To avoid or reduce eddy currents, it is generally known to provide a grooved soft magnetic material, such as electrical steel, within an electric motor. However, this technique has been applied for large devices where the sheet typically has a thickness in the range of about 500 μm or more. In a small application such as the blood pump of the present invention, where one of the columns typically has a diameter on the order of the aforementioned size and the power input is relatively low (e.g., up to 20 watts (W)), eddy currents and related problems were not anticipated. Surprisingly, despite the small diameter of the columns, by providing grooved columns, eddy currents, and thus heat generation and energy consumption, can be reduced. This is advantageous for the operation of a blood pump, which may be operated at high speeds of up to 50,000 revolutions per minute (rpm).

[0014] It will be understood that configurations other than the aforementioned grooved configuration for providing a discontinuous soft magnetic material within the column may be possible. For example, instead of a plurality of sheets, a plurality of wires, fibers, columns, or other elongated elements can be provided to form each of the columns of the drive unit. The wires or the like may be provided in the form of a bundle electrically insulated from each other, for example, using a coating surrounding each wire or an insulating matrix in which the wires are embedded, and may have various cross-sectional shapes such as circular, round, rectangular, square, polygonal, etc. Similarly, particles of a soft magnetic material, wire wool of a soft magnetic material, or other sponge-like or porous structures can be provided, within which the space between regions of the soft magnetic material contains an electrically insulating material such as an adhesive, lacquer, polymer matrix, or the like. The porous, and thus discontinuous, structure of the soft magnetic material may also be formed by a sintered material or a pressed material. In such a structure, an insulating layer may be automatically formed by an oxide layer resulting from oxidation of the soft magnetic material due to exposure to air, so that additional insulating material may be omitted.

[0015] While a sheet of soft magnetic material or other structure can be formed uniformly, i.e., the sheet inside one or all of the pillars can have the same thickness, or the wire can have the same diameter, a non-uniform configuration can be provided. For example, the sheet can have a varying thickness, or the wire can have a varying diameter. More specifically, especially with respect to a laminate of sheets, one or more central sheets can have a greater thickness, while the adjacent sheets towards the ends of the laminate can have a smaller thickness. That is, the thickness of the sheet decreases from the center towards the ends of the laminate, i.e., towards the outermost sheet of the laminate. Similarly, one or more central wires within the bundle of wires can have a greater diameter, while the wires at the edges of the pillars can have a smaller diameter. That is, the diameter of the wire can decrease from the center towards the edges of the bundle, i.e., towards the outermost wire of the bundle. Providing a larger continuous region of the soft magnetic material at the center of the pillar with respect to a cross-section transverse to the longitudinal axis of the pillar, i.e., providing a relatively thick sheet or wire at the center, can be advantageous. This is because it can enhance the magnetic flux passing through the center along the longitudinal axis of each pillar, and the eddy currents at the center are not as significant as those at the sides of the pillar. In other words, such a configuration can be advantageous because the eddy currents in the side regions of the pillar are more significant and can be reduced by the thin sheets or wires in the side regions.

[0016] The weld enables easy fabrication of a core or a part thereof from a discontinuous soft magnetic material. That is, when separating a core, or a post for a core, from a larger workpiece of discontinuous soft magnetic material, the discontinuous soft magnetic material may delaminate or otherwise lose its integrity due to the machining forces applied to the workpiece during the separation process. This is particularly critical due to the very small dimensions of the core, and especially its posts, and can occur even when electrical discharge machining, particularly wire cut electrical discharge machining, is used to separate the core, or its posts, from the workpiece. By using the weld, which is applied onto the workpiece prior to the separation step, the mechanical stability of the discontinuous material is improved. When electrical discharge machining is used to cut out the core or posts from the workpiece, the flow of current to the cutting location is also improved. The weld or group of welds may later form part of the core or posts.

[0017] Specifically, the impeller-side end face of the post, which is oriented across the axis of rotation, exposes the discontinuous material. Accordingly, the weld or group of welds may be disposed on the impeller-side surface of the post. Alternatively or additionally, the weld or group of welds may be disposed on the rear end face of the post, or, in the case where a core including a backplate serving as a yoke is integrally formed with the workpiece as a monoblock, a further weld or further group of welds may be disposed on the rear end face of the backplate.

[0018] Preferably, at least one of the posts, and preferably all of the posts, are arranged substantially perpendicular to at least one longitudinal axis of the posts. At least one of the posts, and preferably all of the posts, may further include a circumferential / peripheral surface disposed around the longitudinal axis of the post and extending along the longitudinal axis, the rear end face being provided at a rear longitudinal end of the circumferential surface, the rear end face facing in a direction away from the impeller. Preferably, the rear end face is substantially perpendicular to the circumferential surface.

[0019] Preferably, the entire surface of the magnetic core or its posts may be covered with welds to bridge all soft magnetic components, such as a sheet of discontinuous material present on the surface. Most preferably, all components of the discontinuous material are bridged. By bridging as many soft magnetic components of the discontinuous material as possible, optimal fabrication can be achieved.

[0020] Preferably, two welds are arranged spaced apart from each other at one end of at least one post. These welds are preferably weld joints. Such weld joints are preferably arranged parallel to each other. Specifically, spaced joints can be welded on the surface of the raw material or workpiece that is intended to have the post cut out after welding.

[0021] Alternatively, or in addition, the weld or group of welds may extend over the side surface of the post. This alternative can produce less eddy current because the welding surface does not cross the magnetic flux compared to welding the end face of the post.

[0022] More than one of at least one weld may be arranged on the same surface side of at least one of the posts, whether the surface is a side surface, an end face, or both. Further, in an alternative, the weld may at least partially surround the side surface of the post.

[0023] Preferably, the weld or group of welds is provided as a weld joint. The joint may have a smaller cross-section compared to a weld covering the entire surface, whereby the joint can produce less additional eddy current.

[0024] Similar to the posts, the backplate may include a discontinuous soft magnetic material. Since the magnetic flux in the backplate is substantially transverse or perpendicular to the axis of rotation, the soft magnetic material of the backplate is preferably discontinuous in a cross-section parallel to the axis of rotation. An exception may be the case where the posts and the backplate are manufactured as a monoblock. Except for that, substantially all of the features and explanations described above regarding the discontinuous material of the posts also apply to the backplate. For example, similar to the posts, the backplate may be grooved, i.e., formed of a plurality of stacked sheets, and the sheets of the backplate are preferably electrically insulated from each other. The sheets of the backplate may extend substantially perpendicular to the sheets of the posts. As explained above, eddy currents, and thus heat generation and power consumption, can be reduced. However, the backplate may alternatively be formed of a continuous, i.e., solid, soft magnetic material.

[0025] Similar to the posts, the backplate is preferably made of a soft magnetic material such as electrical steel (magnetic steel), or other materials suitable for closing the magnetic flux circuit, preferably cobalt steel. The diameter of the backplate can be in the range of 3 mm to 9 mm, for example, 5 mm or in the range of 6 mm to 7 mm. The thickness of the backplate can be in the range of 0.5 mm to 2.5 mm, for example, 1.5 mm. The outer diameter of the blood pump can be in the range of 4 mm to 10 mm, preferably 7 mm. The outer diameter of the configuration of a plurality of posts can be in the range of 3 mm to 8 mm, for example, in the range of 4 mm to 7.5 mm, preferably 6.5 mm.

[0026] As described above, the posts are made of a soft magnetic material such as electrical steel (magnetic steel). The posts and the backplate can be made of the same material. Preferably, the drive unit including the posts and the backplate is made of cobalt steel. The use of cobalt steel contributes to the reduction of the pump size, especially the diameter. Since it has the highest magnetic permeability and the highest saturation magnetic flux density among all magnetic steels, cobalt steel generates the maximum amount of magnetic flux for the same amount of material used.

[0027] The dimensions of the column, in particular the length and cross-sectional area, can vary and may depend on various factors. In contrast to the dimensions of the blood pump, such as the outer diameter, which depend on the application of the blood pump, the dimensions of the column are determined by electromagnetic characteristics that are adjusted to achieve the desired performance of the drive unit. One of the factors is the magnetic flux density to be achieved through the minimum cross-sectional area of the column. The smaller the cross-sectional area, the higher the current required to achieve the desired magnetic flux. However, the higher the current, the more heat is generated in the wire of the coil due to electrical resistance. This means that a "thin" column is preferred to reduce the overall size, but this will require a high current and thus generate undesirable heat. The heat generated in the wire also depends on the length and diameter of the wire used for the coil winding. To minimize the winding losses (referred to as "copper loss" or "copper power loss" when copper wire is used, as is usually the case), a short wire length and a large wire diameter are preferred. In other words, when the wire diameter is small, more heat is generated at the same current compared to a thicker wire. The preferred wire diameter is from 0.05 mm to 0.2 mm, for example, 0.1 mm, etc. Further factors affecting the dimensions of the column and the performance of the drive unit are the number of turns of the coil and the outer diameter of the winding, i.e., the column including the winding. A number of turns greater than one can be arranged in layers around each column, for example, two or three layers can be provided. However, the more layers there are, the more heat will be generated due to the increased length of the wire in the outer layer with a larger winding diameter. The increased length of the wire can generate more heat due to the higher resistance of the longer wire compared to a shorter one. Therefore, a single layer of windings with a small winding diameter would be preferred. The typical number of turns, which next depends on the length of the column, can be from about 50 to about 150, for example, 56 or 132. Regardless of the number of turns, the coil winding is made of an electrically conductive material, in particular a metal such as copper or silver. Silver can be preferred over copper because it has an electrical resistance that is about 5% lower than that of copper.

[0028] Preferably, the pillar has a triangular cross-section across the axis of rotation, and the soft magnetic sheet of soft magnetic material is preferably oriented in or parallel to a plane passing through the bisector of the triangular cross-section. This orientation has the advantage that the longest soft magnetic sheet is arranged in the center of the pillar. In the mounted state of the pillar, the bisector can extend through the radially innermost corner of the triangular cross-section and preferably also through the axis of rotation.

[0029] In a further aspect of the invention, a method for manufacturing a magnetic core, or a part of a magnetic core, for a drive unit of an intravascular blood pump is proposed. It comprises the following steps in sequence: providing a workpiece comprising or consisting of a discontinuous soft magnetic material, wherein the soft magnetic material is discontinuous with respect to electrical conductivity within the cross-section of the workpiece and a magnetic core or a part thereof is to be manufactured from the workpiece; providing a weld at the surface of the workpiece, whereby the weld bridges at least one discontinuity with respect to electrical conductivity within the discontinuous soft magnetic material of the workpiece; and separating the magnetic core, or a part of the magnetic core, from the workpiece after providing the weld.

[0030] At least a part of the weld can remain on the pillar after separating the magnetic core, or a part of the magnetic core, from the workpiece. Thereafter, for example, sheets of laminated soft magnetic material can be firmly held together by the weld.

[0031] According to a preferred embodiment, the step of separating the magnetic core, or a portion of the magnetic core, from the workpiece includes separating at least one of the columns from the workpiece by electric discharge machining (EDM), particularly wire cut EDM. Before machining the columns from the workpiece of the soft magnetic material, one dimension of the workpiece is preferably pre-cut to the length of the columns, such that the pre-cut workpiece has the same outer dimensions as the length of the columns. At the end faces defining the length of the columns, welds can be provided before cutting out the columns. For example, one or preferably two weld seams can be spaced apart across each of the surfaces of the pre-cut workpiece that will later form the cross-sectional end faces of the columns to be cut out from the workpiece. Preferably, all the soft magnetic components of the discontinuous soft magnetic material of the columns to be cut out are electrically connected by the welds. The weld seams can extend over the cross-sections of more than one column to be cut out from the workpiece. Specifically, the weld seams preferably extend from one end of the pre-cut workpiece to the opposite end of the pre-cut workpiece, and it also extends across at least one cross-section of the columns to be cut out. More than one column can be machined from one pre-cut workpiece. The cross-sections of the columns to be cut out can be appropriately distributed within the pre-cut material to utilize a high percentage of the material. As described above, the discontinuous soft magnetic material of the workpiece can be a laminated material including a laminate of soft magnetic sheets. For example, the triangular cross-sections of two columns to be cut out from the workpiece can be oriented such that the bisectors of the corners in each of the triangular cross-sections are aligned with the lamination plane of the soft magnetic material, the bisectors are spaced apart from each other, and the corners of the triangular cross-sections having the bisectors are oriented in opposite directions. The above measures help to efficiently generate the columns from the workpiece.

[0032] Preferably, for triangular columns, the weld or weld group can be arranged along one side of the triangular cross-section of the column. At this time, the column can be mechanically stabilized from this side. In this way, the laminated sheets of the soft magnetic material, preferably all the sheets of the column, can be electrically connected by the welds.

[0033] Preferably, at least one welded portion is produced by laser welding. It is also possible to apply double laser welding in which the location of the welded portion is welded at least one more time. This can be useful, for example, for bridging the gap between two adjacent sheets of stacked soft magnetic material.

[0034] The cut-out core, or part of the core, in particular the cut-out post, may have burrs removed at at least one welded portion after separating the core, or part of the core, from the workpiece. The burrs can penetrate into the electrical insulation, depending on the case.

[0035] The above summary and the following detailed description of the preferred embodiments will be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the present disclosure, reference is made to the drawings. However, the scope of the present disclosure is not limited to the specific embodiments disclosed in the drawings.

Brief Description of the Drawings

[0036]

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DETAILED DESCRIPTION OF THE INVENTION

[0037] Referring to FIG. 1, a cross-sectional view of the blood pump 1 is shown. The blood pump 1 includes a pump casing 2 having a blood flow inlet 21 and a blood flow outlet 22. The blood pump 1 is designed as an intravascular pump, also called a catheter pump, and is deployed into a patient's blood vessel using a catheter 25. The blood flow inlet 21 is at the end of a flexible cannula 23 that can be placed through a heart valve, such as the aortic valve, during use. The blood flow outlet 22 is located within the side surface of the pump casing 2 and can be placed within a cardiovascular vessel, such as the aorta. The blood pump 1 is electrically connected to an electrical wire 26 that extends through the catheter 25 for supplying power to the blood pump 1 to drive the pump 1 using a drive unit 4, as will be described in more detail below.

[0038] When the blood pump 1 is intended to be used within a long-term implant, i.e., in a situation where the blood pump 1 is implanted in a patient for weeks or even months, the power is preferably supplied using a battery. Since the patient is not connected to a base point by a cable, this allows the patient to move. The battery can be carried by the patient and supply electrical energy to the blood pump 1, for example, wirelessly.

[0039] Blood is conveyed along a passage 24 connecting a blood flow inlet 21 and a blood flow outlet 22 (the blood flow is indicated by the arrow). An impeller 3 is provided to convey the blood along the passage 24 and is mounted in a pump casing 2 so as to be rotatable about a rotating shaft 10 using a first bearing 11 and a second bearing 12. The rotating shaft 10 is preferably the longitudinal axis of the impeller 3. Both bearings 11 and 12 are contact bearings in this embodiment. However, at least one of the bearings 11 and 12 could be a non-contact bearing, such as a magnetic or hydrodynamic bearing. The first bearing 11 is a pivot bearing having a spherical bearing surface that allows rotational movement and a certain degree of pivotal movement. A pin 15 is provided that forms one of the bearing surfaces. The second bearing 12 is disposed within a support member 13 for stabilizing the rotation of the impeller 3, and the support member 13 has at least one opening 14 for the blood flow. When the impeller 3 rotates, blades 31 for conveying the blood are provided on the impeller 3. The rotation of the impeller 3 is caused by a drive unit 4 magnetically coupled to a magnet 32 at an end portion of the impeller 3. The illustrated blood pump 1 is a hybrid blood pump, and the main direction of the flow is axial. It will be understood that the blood pump 1 could also be a purely axial blood pump depending on the configuration of the impeller 3, particularly the blades 31.

[0040] The blood pump 1 includes an impeller 3 and a drive unit 4. The drive unit 4 includes a plurality of posts 40, such as six posts 40, only two of which are visible in the cross-sectional view of FIG. 1. The posts 40 are arranged parallel to the rotation axis 10. More specifically, the longitudinal axis of each of the posts 40 is parallel to the rotation axis 10. One end of the post 42 is disposed adjacent to the impeller. A coil winding 44 is disposed around the post 40. The coil winding 44 is sequentially controlled by control to create a rotating magnetic field. The control unit part is a printed wiring board 6 connected to the electric wire 26. The impeller has magnets 32, which are formed as multi-piece magnets in this embodiment. The magnets 32 are disposed at the end of the impeller 3 facing the drive unit 4. The magnets 32 are arranged to interact with the rotating magnetic field to cause the rotation of the impeller 3 around the rotation axis 10.

[0041] To close the magnetic flux path, a back plate 50 is disposed at the end of the post 40 opposite to the impeller side of the post. The post 40 serves as a magnetic core and is made of a suitable material, particularly a soft magnetic material such as steel or a suitable alloy, particularly cobalt steel. Similarly, the back plate 50 is made of a suitable soft magnetic material such as cobalt steel. The back plate 50 enhances the magnetic flux, which enables the reduction of the overall diameter of the blood pump 1, which is important for an intravascular blood pump. For the same purpose, a yoke 37, i.e., an additional impeller back plate, is provided in the impeller 3 on the side of the magnet 32 facing away from the drive unit 4. The yoke 37 in this embodiment has a conical shape to guide the blood flow along the impeller 3. The yoke 37 can also be made of cobalt steel. One or more washout channels extending towards the central bearing 11 can be formed in the yoke 37 or the magnet 32.

[0042] Figure 2 shows a cross-sectional view of a preferred embodiment of the drive unit-impeller configuration for the blood pump according to FIG. 1. As can be seen in FIG. 2, the impeller-side end 420 of the post 40 does not radially extend beyond the winding 44. Rather, the cross-section of the post 40 is constant in the direction of the longitudinal axis LA of the post 40. Thus, the posts 40 are prevented from approaching each other. This is because this can cause a partial magnetic short circuit, resulting in a reduction in the power of the electric motor of the blood pump.

[0043] The drive unit according to FIG. 2 can include at least 2, at least 3, at least 4, at least 5, or preferably 6 posts 40. A greater number of posts 40, such as 9 or 12, may also be possible. Due to the cross-sectional view, only two posts 40 are visible. The posts 40 and the back plate 50 form the magnetic core 400 of the drive unit 4, which may have a diameter of less than 10 mm.

[0044] The posts 40 can be made of a discontinuous soft magnetic material that is discontinuous with respect to electrical conductivity. The discontinuous soft magnetic material is made of a ferromagnetic material and includes a plurality of sheets 85 laminated to each other. The lamination direction is arranged in the direction of the longitudinal axis LA of the post 40 and is labeled by the arrow DL. As shown in the figure, the posts 40 are arranged parallel to the rotation axis 10.

[0045] The spacer 7 is disposed around the post 40. It is made of a magnetically inert material and has the purpose of keeping the distance of the posts 40 at their impeller-side ends 420 constant. The spacer 7 will be described in more detail with respect to FIGS. 3A-3C. The impeller-side end 424 of the coil winding 44 extends up to the spacer 7. A back plate 50 is provided at the other end of the post 40. According to the embodiment shown in FIG. 2, the back plate 50 has a recess for receiving the post 40 therein. More specifically, it includes a first layer 51 having an opening 511 for the rear end 450 of the post 40. The back plate 50 will be described in more detail with respect to FIGS. 4A-4C.

[0046] It is conceivable to implement an embodiment of the blood pump 1 having any combination of the following three features: the impeller-side end portion 424 of the column does not radially expand beyond the impeller-side end portion of the winding 44; a magnetically inert spacer 7 is provided between the columns 40; and a back plate 50 having a recess for receiving the rear end portion 450 of the column 40.

[0047] Figures 3A to 3C respectively show a perspective view, a front view, and a side view of the spacer 7. The spacer 7 generally has the form of a disc or a wheel with a through hole 75 in the center. The spacer 7 includes openings 71 for each of the columns. For an embodiment having six columns 40, as shown, there are six openings 71. Spaced spokes 72 are arranged between the openings 71. When the columns 40 are inserted into the openings 71, the spaced spokes 72 keep the distance between the columns 40 constant. Further, the spacer 7 includes an outer rim 73 and an inner rim 74 that connect adjacent spaced spokes 72 and stabilize the spacer. The spacer 7 is made of titanium, a paramagnetic material that avoids magnetic short-circuiting when disposed between the impeller-side end portions 420 of the columns 40. Titanium provides high mechanical strength, which enables the production of the spacer 7 with a small thickness. This is advantageous in terms of consumption of construction space.

[0048] FIG. 4A shows a perspective view of the first layer 51 of the backplate 50. The first layer 51 has the overall shape of a disc or wheel with a central hole 515. The first layer 52 includes an opening 511 in which the rear end portion 450 of the post 40 will be disposed. The first layer 51 includes spaced spokes 512 disposed between the openings 511. One purpose of the spaced spokes 512 is to keep the distances of the rear end portions 450 of the posts 40 constant from each other. Further, the first layer 51 includes an outer rim 513 and an inner rim 514 that connect the spaced spokes 512 at the outer and inner radial ends of the opening 511, respectively. The first layer 51 can be made of a discontinuous soft magnetic material that is discontinuous with respect to electrical conductivity. It can be composed of several ferromagnetic sheets 85, particularly, as shown in FIG. 4A, three sheets. The sheets 85 are laminated to each other using an electrically non-conductive material to form a discontinuous soft magnetic material. The lamination direction DL is generally parallel to the sheets 85, and the main spreading direction of the sheets defines the lamination plane. Within the backplate 50, the sheets 85 are perpendicular to the rotation axis 10. At the center of the first layer 51, a hole 515 is disposed. Its purpose can be to facilitate the assembly of the first layer 51 and the second layer 52, for example, to center the first and second layers 51, 52.

[0049] Figure 4B shows a perspective view of the second layer 52 of the backplate 50. The second layer 52 substantially has the form of a disc having a central hole 525 corresponding to the hole 515 in the first layer 51. The second layer 52 has no opening for the rear end portion of the column 40. Instead, the second layer 52 has a contact plane 526 facing the rear end portion 450 of the column 40. The rear end portion 450 of the column is in contact with the contact plane 526 of the second layer 52 of the backplate 50 in the assembled state of the drive unit, and transmits magnetic flux between the rear end portion 450 of the column 40 and the backplate 50. Since all the rear end portions 450 of the column 40 are in contact with the contact plane 526, magnetic flux can be exchanged between the columns 40, and a magnetic zero point can occur within the second layer 52. To enable this, the second layer 52 is made of a soft magnetic material. The soft magnetic material can be a discontinuous soft magnetic material that is discontinuous with respect to electrical conductivity, and can include sheets 85 laminated with each other having the same structure as described above with respect to the first layer 51. As an example, three sheets 85 as shown in Figure 4B can constitute the second layer 52. Within the second layer 52, the lamination direction D is perpendicular to the rotation axis 10. The sheet 85 is ferromagnetic and electrically conductive, while the intermediate layer between the sheets 85, not explicitly shown, is non-ferromagnetic and electrically non-conductive. This type of discontinuous soft magnetic material reduces eddy currents that would otherwise be generated in larger quantities due to changes in magnetic flux. The hole 525 at the center of the second layer 52 can have the purpose of facilitating the assembly of the first layer 51 and the second layer 52, for example, centering the first and second layers 51, 52.

[0050] Figure 4C shows a cross-section of the backplate 50. It is composed of a first layer 51 and a second layer 52 joined to each other on their main surfaces having the largest spread. The joining between the first layer 51 and the second layer 52 of the backplate 50 can be established in the same way as between the sheets 85 of the first and second layers 51, 52. The through-holes 515 and 525 of the first layer 51 and the second layer 52 are aligned with each other to align the first and second layers 51, 52. By stacking the first and second layers 51, 52, the opening 511 is closed at one end by the second layer 52, thereby forming a recess 501 for accommodating the rear end portion 450 of the column 40. At the base of the recess 501, a contact plane 526 is formed. When the column 40 is inserted into the recess 501, its rear end portion 450 contacts the contact plane 526. Further, the position of the column 40 is fixed by spaced spokes 512 surrounding each of the columns 40 together, as well as by outer and inner rims 513, 514. In this way, a magnetic connection is established between the second layer 52 and the rear end surface 45 of the column 40 at the contact plane 526, and in addition, a second magnetic connection is established between the column 40 and the above-described surrounding portion of the first layer 51. However, the main part of the magnetic flux is transmitted through the contact plane 526. Preferably, the surface at the rear end portion 450 of the column 40 has a predetermined flatness, and the contact plane 526 also has a predetermined flatness. In this way, the gap between the surface 45 at the rear end portion 450 of the column 40 and the contact plane 526 can preferably be maintained less than a specific size of less than 10 μm. This improves the transmission of magnetic flux between the column 40 and the backplate 50. Preferably, there is no additional material between the surface 45 at the rear end portion 450 of the column 40 and the contact plane 526. In this embodiment of the present invention, the transmission of magnetic flux through the surface 45 and the backplate 50 is independent of the way of fixing the column 40 to the backplate 50.

[0051] Figures 5A to 5D show the preparation steps for the generation of the column 40. Figure 5A shows a perspective view of a plate 8 of a discontinuous soft magnetic material that is discontinuous with respect to electrical conductivity, also referred to hereinafter as the workpiece.

[0052] In FIG. 5A, a width W for cutting a workpiece bar 81 from the plate 8 is marked on the plate 8. The width W of the workpiece bar 81 is the same as the length of the column 40 to be fabricated from the workpiece bar 81. FIG. 5B shows an enlarged view of the portion marked by the rectangle R in FIG. 5A. Here, a stack of discontinuous soft magnetic material sheets 85 can be visually recognized. The direction of the stack DL extends along the main plane of the plate 8 and thus forms a stacking plane.

[0053] FIG. 5C shows the workpiece bar 81 cut from the plate 8 as individual pieces of discontinuous material. FIG. 5D shows an enlarged view of the portion marked by the rectangle R in FIG. 5C. The sheet 85 of the workpiece bar 81 can be visually recognized in this enlargement.

[0054] FIG. 6A shows the workpiece bar 81 of FIGS. 5C and 5D forming a base for a welding step for cutting out the column 40 from the bar 81. A plurality of cross-sections 84 of the column 40 to be fabricated from the bar 81 are shown on the side surface of the bar 81 facing left in FIG. 6A. The column 40 is fabricated by cutting out these cross-sections 84 from the bar 81. Since the width W of the bar 81 corresponds to the length of the column 40, the side surfaces 811 and 812 of the bar 81 become the end faces at the impeller side end 420 and the rear end 450 of the column 40.

[0055] Figure 6B shows the next preparatory step before cutting out the column 40. Two weld seams 82 and 83 are welded on the surface 811 of the bar 81 at a distance from each other and across each of the cross-sections 84 of the column 40 to be cut out. The weld seams 82 and 83 extend perpendicular to the lamination direction DL of the sheet 85. In this way, the sheets of discontinuous material are connected to each other. Instead of two weld seams, a single weld seam may be provided. In addition, similar weld seams may be provided on the opposite side surface 812 of the bar 81. The sheet 85 has a better mechanical connection to each other due to the weld seams 82 and 83 and is further electrically connected. The latter has the advantage that the current can flow from any position of the discontinuous soft magnetic material intended to be the column 40 to each position of the electrical connection of the bar 81 that may be required, for example, for electrical discharge machining. In this way, electrical discharge machining is greatly facilitated. Furthermore, since the cut-out column 40 cannot be disassembled by delamination, a higher process reliability is achieved. Preferably, laser welding is applied. It may be advantageous to apply the welding power to the same weld area two or more times. In Figure 6C, the portion of the bar 81 labeled by the rectangle R is shown enlarged.

[0056] Therefore, Figure 6C shows a plurality of cross-sections 84 of the column 40 to be cut out from the bar 81. The cross-sections 84 have a substantially triangular shape. As shown, the corners may have rounded edges. The convex side 842 of the triangle shown on the left side of the cross-section 84 in Figure 6C has a convex shape. This type of cross-section 84 is advantageous for making full use of the available construction space inside the cylindrical pump housing 2. The bisector of the corner 841 of the cross-section 84 on the side opposite to the convex side 842 of the cross-section 84 is aligned with the lamination direction DL. In this way, the sheet 85 extends symmetrically through the cross-section 84.

[0057] FIG. 7 shows the column 40 cut out from the bar 81. The weld seams 82 and 83 still exist on the surface 45 at the rear end portion 450 of the bar 81 so that they can be seen on the surface. The column 40 has a constant cross-section 84 along its entire length. The weld seams 82 and 83 are removed after the column 40 is cut out.

[0058] FIG. 8 shows another configuration of two cross-sections 84 on the side surface 811 of the workpiece bar 81. In contrast to the workpiece bar 81 shown in FIGS. 6A - 6C, the side surface 811 of the workpiece bar 81 in FIG. 8 has a size that allows the two cross-sections 84 to be arranged adjacent to each other in a direction perpendicular to the lamination direction DL. The cross-sections 84 are oriented such that, with respect to the lamination direction DL, the bisector B of the corner on the side opposite to the convex side 842 of each of the cross-sections 84 is aligned with the lamination direction DL. By arranging the cross-sections 84 along the bar 81 in this way, material can be saved. The resulting waste material is reduced. Depending on the thickness of the bar 81 and the required cross-sectional dimensions of the column 40, it is conceivable to stack even more cross-sections 84 of the column 40 in a direction perpendicular to the lamination direction DL. The weld seams 82 and 83 each extend across each of the cross-sections 84. The weld seams 82, 83 also extend across the entire side surface 811 of the bar 81 in a direction perpendicular to the lamination direction DL. In this way, all the sheets 85 of the discontinuous soft magnetic material of the bar 81 are connected to each other.

[0059] FIG. 9 shows an example of the column 40 cut out from the welded bar 81, that is, a front view on one of the end faces of the column 40. As shown in FIG. 9, a single weld seam 86 of a considerable width that can cover more than about one-third of the height of the triangular cross-section 84 extends along the convex side 842 of the cross-section 84. The weld seam 86 extends perpendicular to the lamination direction DL and connects all its sheets. Also in this case, similar to the previous one, the bisector B of the corner 841 on the side opposite to the convex side 842 is aligned with the lamination direction DL.

[0060] FIG. 10 shows a second embodiment of the drive unit - impeller configuration for the blood pump 1 according to FIG. 1. Similar to the first embodiment shown in FIG. 2, the impeller - side end 420 of the column 40 does not radially expand beyond the winding 44. Rather, the cross - section of the column 40 is constant in the direction of the longitudinal axis LA of the column 40. Thus, the columns 40 are prevented from approaching each other. This is because this can cause a partial magnetic short - circuit, resulting in a reduction in the power of the electric motor of the blood pump.

[0061] The drive unit according to FIG. 10 can include at least 2, at least 3, at least 4, at least 5, or preferably 6 columns 40. A greater number of columns 40, such as 8, 10, or 12, may also be possible. Only 2 columns 40 are visible due to the cross - sectional view. The columns 40 and the back - plate 50 form the magnetic core 400 of the drive unit 4, which may have a diameter of less than 10 mm.

[0062] This embodiment is different from the first embodiment shown in FIG. 2 due to the different structure of the magnetic core. Here, the magnetic core 400 includes the magnetic - component elements of the drive unit 4, which are the columns 40 and the back - plate 50, as one single part or monoblock. The monoblock is made of a discontinuous soft - magnetic material. The discontinuous soft - magnetic material is discontinuous with respect to electrical conductivity. As shown in the figure, it includes a plurality of sheets 85 of ferromagnetic material that are laminated to each other to form a monoblock 9 as shown in FIG. 11C. The lamination direction DL is parallel to the rotation axis 10.

[0063] The coil winding 44 extends to the impeller side end 420 of the column 40. This has the advantage that the magnetomotive force can be generated along the entire column 40. The magnetic core 400 includes a protrusion 401 at the rear end 450 of the column 40 that protrudes radially with respect to the column 40. This protrusion 401 can serve as a stopper for the coil winding 44 towards the back plate 50. Since the integrated magnetic core 400 has high rigidity between the back plate 50 and the column 40, the spacer between the columns 40 at the impeller side end 420 of the column can be omitted. The integrated magnetic core 400 provides the advantage that an optimal magnetic connection between the column 40 and the back plate 50 can be achieved. The magnetic core 400 can have a diameter of less than 10 mm.

[0064] Figures 11A to 11C show the steps of manufacturing the magnetic core 400 for the drive unit 4 of the drive unit - impeller configuration as shown in Figure 10. Figure 11A shows in perspective view a cubic monoblock 9 forming a workpiece for manufacturing the magnetic core 400. The monoblock 9 is made of a discontinuous soft magnetic material that is discontinuous with respect to electrical conductivity. It includes sheets 85 oriented in a lamination direction DL extending along the main plane of the sheet 85. The sheets 85 are each joined to their respective adjacent sheets by a bonding layer of an electrically non - conductive material not explicitly shown in Figures 11A to 11C.

[0065] Figure 11B shows the magnetic core 400 in a semi - finished state, for example, transformed, where it is machined from the cubic monoblock 9 into a substantially cylindrical body 94. In this machining step, the protrusion 401 is fabricated. The reduced - diameter section 404 of the body 94 that forms the circumferential surface of the column 40 of the magnetic core 400 is fabricated to have a diameter corresponding to the outer radius of the outermost convex side surface 842 of the column 40.

[0066] Next, the body 94 can be further fabricated to produce a magnetic core 400 as shown in FIG. 11C. For this production step, electrical discharge machining can be used. In particular, wire cut electrical discharge machining can be applied to produce a groove hole 49 that separates the columns 40 from each other. A space for the coil winding 44 is provided inside the groove hole. At the base of the groove hole 49, an intermediate area 59 of the integral back plate 50 extends between the rear ends of the columns 40. The intermediate area is integral with the columns 40 and the back plate 50. Therefore, the entire magnetic core is formed by the monoblock 9.

[0067] The lamination direction DL within the magnetic core 400 is such that it is parallel to the rotation axis 10. It can be tolerated that the lamination direction DL within the base plate 50 is not parallel to the magnetic flux between the columns 40 within the base plate 50. It is also possible to fabricate the magnetic core 400 from coiled soft magnetic sheet material separated by electrically non-conductive layers. At this time, the lamination direction DL within the base plate 50 is always in the circumferential direction, which is advantageous for avoiding eddy currents within the magnetic flux within the base plate 50.

[0068] Figures 12A - 12C show how one or more welds can be provided on the surface of an integrated core as fabricated according to Figures 11A - 11C. Thus, in the illustrated embodiment, three weld seams 82, 83 are provided on one side surface of the cubic monoblock 9. The weld seams 82, 83 are welded at a distance from each other and across the cross-section of the body 94 to be cut out from the monoblock 9. The weld seams 82, 83 extend perpendicular to the lamination direction DL of the sheet 85. In this way, the sheets of discontinuous soft magnetic material are connected to each other. Instead of the three weld seams, more weld seams or a single wide weld may be provided. Additionally, similar weld seams may be provided on the opposite side of the monoblock 9 (not shown). As an alternative to, or in addition to, the welds on the opposite side surface, one or more weld seams may be provided at the level of the backplate 50 on the side surface of the monoblock 9 so as to completely or at least partially surround the backplate 50. The sheets 85 have a better mechanical connection to each other due to the weld seams 82, 83 and are further electrically connected. The latter has the advantage that current can flow from any location of the discontinuous soft magnetic material to each location of the electrical connection of the body 94 that may be required, for example, for electrical discharge machining. In this way, electrical discharge machining is significantly facilitated. Further, a higher process reliability is achieved because the backplate-post unit cut out from the body 94 cannot be disassembled by delamination. Preferably, laser welding is applied. It may be advantageous to apply the welding power to the same weld twice or even a greater number of times.

[0069] Figures 13A - 13J show various embodiments of a column as seen in cross - section. Figures 13A - 13D show embodiments in which the column is grooved, i.e., formed of a plurality of sheets 171 insulated from each other by an insulating layer 172. The insulating layer 172 can include an adhesive, lacquer, baked enamel, or the like. Figures 13A and 13B show embodiments in which the thickness of the sheets 171 is uniform. The thickness can be in the range of 25 μm to 450 μm. The sheet 171 shown in Figure 13A has a greater thickness than the sheet 171 shown in Figure 13B. The sheets in Figure 13C have a varying thickness, with the central sheet having the greatest thickness and the outermost sheet having the smallest thickness. This can be advantageous because eddy currents within the side regions of the column are more significant and can be reduced by the thinner sheets. Eddy currents within the central region are not as significant, and the relatively thick central sheet can help improve the magnetic flux. The orientation of the sheets 171 can vary as long as the soft - magnetic material shown in cross - section, i.e., the soft - magnetic material within the cross - section transverse to the direction of the magnetic flux, is discontinuous or segmented, as exemplarily shown in Figure 13D.

[0070] Figures 13E and 13F show embodiments in which the column 141 is formed by a bundle of wires 181 insulated from each other by an insulating material 182. The insulating material 182 can exist as a coating for each of the wires 181 or can be the base material in which the wires 181 are embedded. In the embodiment of Figure 13E, all the wires have the same diameter, whereas in the embodiment of Figure 13F, similar to the embodiment shown in Figure 13C having sheets with varying thickness, the central wire has the greatest diameter and the outer wires have smaller diameters. As shown in Figure 13G, wires 181 of different diameters can be mixed, which can increase the total cross - sectional area of the soft - magnetic material compared to embodiments in which all the wires have the same diameter. Further alternatively, in order to further minimize the insulating layer 184 between the wires 183, the wires 183 can have a polygonal cross - sectional area, such as rectangular, square, etc.

[0071] Alternatively, the discontinuous cross-section of the pillar 141 may be created by metal particles 185 embedded in a polymer matrix 186 as shown in FIG. 13I, or by steel wool or other porous structures impregnated with an insulating matrix. The porous, and thus discontinuous, structure of the soft magnetic material may also be generated by a sintering process or a high-pressure molding process, in which case the insulating matrix may be omitted since an insulating layer is automatically formed by oxidation of the soft magnetic material due to exposure to air. Further alternatively, the pillar 141 may be formed of a rolled sheet 187 of soft magnetic material, in which case the layers of the rolled sheet 187 are separated by an insulating layer 188 as shown in FIG. 13J. This also results in a discontinuous cross-section in the sense of the present invention that reduces eddy currents in the pillar 141 or the pillar 40.

Claims

1. An intravascular blood pump (1) for percutaneous insertion into a patient's blood vessel, comprising: a pump casing (2) having a blood flow inlet (21) and a blood flow outlet (22); an impeller (3) disposed within the pump casing (2) so as to be rotatable about a rotation axis (10), the impeller (3) having blades (31) sized and shaped to convey blood from the blood flow inlet (21) to the blood flow outlet (22); a drive unit (4) for rotating the impeller (3), the drive unit (4) including a plurality of posts (40) disposed around the rotation axis (10) and a back plate (50) connecting the rear ends (450) of the posts (40), the posts (40) and the back plate (50) forming a magnetic core (400) of the drive unit (4); a coil winding (44) disposed around each of the posts (40), the coil winding (44) being controllable to create a rotating magnetic field; and in the intravascular blood pump (1), the impeller (3) includes a magnet structure (32) arranged to interact with the rotating magnetic field to cause rotation of the impeller (3). The intravascular blood pump (1) is characterized in that the magnetic core (400) or a part thereof includes or consists of a discontinuous soft magnetic material that is discontinuous with respect to electrical conductivity in a cross-section, and at least one welding portion (82, 83, 86) is provided separately from the back plate (50) on the surface (811) of the discontinuous soft magnetic material, and the welding portion (82, 83, 86) bridges at least one discontinuity with respect to electrical conductivity in the discontinuous soft magnetic material.

2. The intravascular blood pump (1) according to claim 1, characterized in that at least one of the at least one welding portion (82, 83, 86) is disposed on the rear end face (45) of the post.

3. The intravascular blood pump (1) according to claim 1, characterized in that at least one of the at least one welding portion (82, 83, 86) is disposed on the end face of the post (40) on the impeller side.

4. The intravascular blood pump (1) according to claim 1, wherein at least one of the at least one welding portion (82, 83, 86) is disposed on the impeller-side end face of the column (40), and at least one additional welding portion (82, 83, 86) is disposed on the rear end face (45) of the column (40). The intravascular blood pump (1) is characterized by this.

5. The intravascular blood pump (1) according to any one of claims 1 to 4, wherein the at least one welding portion (82, 83, 86) includes two welding portions (82, 83), and the two welding portions (82, 83) are spaced apart from each other at one end (450) of the column (40). The intravascular blood pump (1) is characterized by this.

6. The intravascular blood pump (1) according to any one of claims 1 to 5, wherein at least one of the at least one welding portion (82, 83, 86) extends onto the side surface of the column (40). The intravascular blood pump (1) is characterized by this.

7. The intravascular blood pump (1) according to claim 6, wherein at least one of the at least one welding portion (82, 83, 86) that extends onto the side surface of the column (40) at least partially surrounds at least one of the columns (40). The intravascular blood pump (1) is characterized by this.

8. The intravascular blood pump (1) according to any one of claims 1 to 7, wherein the at least one welding portion (82, 83, 86) includes two or more welding portions, and the two or more welding portions are disposed on the same surface side of the column (40). The intravascular blood pump (1) is characterized by this.

9. The intravascular blood pump (1) according to any one of claims 1 to 8, wherein the at least one welding portion (82, 83, 86) includes a welded joint that bridges the at least one discontinuity regarding the electrical conductivity within the discontinuous soft magnetic material. The intravascular blood pump (1) is characterized by this.

10. The intravascular blood pump (1) according to any one of claims 1 to 9, wherein at least one of the columns (40) includes a laminate of a soft magnetic material having a soft magnetic sheet (85) oriented parallel to its longitudinal axis (LA). The intravascular blood pump (1) is characterized by this.

11. The intravascular blood pump (1) according to claim 10, wherein at least one of the columns (40) has a triangular cross-section (84) in a direction transverse to the rotation axis (10), and the soft magnetic sheet (85) of a soft magnetic material is oriented in a plane passing through or parallel to the bisector (B) of the triangular cross-section (84). The intravascular blood pump (1) is characterized by this.

12. A method for manufacturing a magnetic core (400) for a drive unit (4) of an intravascular blood pump (1), or a part of the magnetic core (400), comprising the following steps: - Providing a workpiece (8, 81) of a discontinuous soft magnetic material, wherein the soft magnetic material is discontinuous with respect to electrical conductivity within the cross-section of the workpiece (8, 81), and the magnetic core (400), or the part of the magnetic core (400), is to be manufactured from the workpiece (8, 81). - Providing welds (82, 83, 86) on the surface (811) of the workpiece (8, 81), whereby the welds (82, 83, 86) bridge at least one discontinuity with respect to electrical conductivity within the discontinuous soft magnetic material of the workpiece (8, 81). A method characterized in that after providing the welds, the magnetic core (400), or the part of the magnetic core (400), is separated from the workpiece (8, 81).

13. The method according to claim 12, characterized in that after separating the magnetic core (400), or the part of the magnetic core (400), from the workpiece (8, 81), at least a part of the welds (82, 83, 86) remains on the magnetic core (400), or the part of the magnetic core (400).

14. The method according to claim 12 or 13, characterized in that the separation of the magnetic core (400), or the part of the magnetic core (400), from the workpiece (8, 81) includes separating at least one of the columns (40) from the workpiece (8, 81) by electrical discharge machining.

15. The method according to any one of claims 12 to 14, characterized in that at least one of the welds (82, 83, 86) is produced by laser welding, or by double application of a welding laser, in particular, double laser welding.

16. A method according to any one of claims 12 to 15, characterized in that the intravascular blood pump (1) is an intravascular blood pump according to any one of claims 1 to 11.

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